Centrifugal blasting wheel

ABSTRACT

A centrifugal blasting wheel is provided which permits rapid and easy blade removal and replacement by providing: a control cage and impeller which can be removed from a central opening defined by the inner ends of the radially extending blades; a blade holding means which utilizes the spacers holding the wheel side plates apart to engage a holding shoulder on the blades to prevent further radial outward movement; and a removable centering plate mounted in the central opening to prevent radial inward movement.

1451 Jan. 15,1974

Freeman Ardee H. Freeman, Granger, Ind.

Wheelabrator-Frye, Inc., NY.

Attorney-McDougalI, Hersh & Scott Inventor:

New York,

[73] Assignee:

[22] Filed: Apr. 5, 1972 ABSTRACT Appl. No.2 241,226

A centrifugal blasting wheel is provided which permits [52] US. Cl. 51/9 rapid and easy blade removal and replacement by viding: a control cage and impeller which can be removed from a central opening defined by the inner ends of the radially extending blades; a blade holdin means which utilizes the spacers holdin side plates apart to engage a holdin B24c 5/06 [58] Field of Int.

g the wheel References Cited UNITED STATES PATENTS g shoulder on the ades to prevent further radial outward movement;

51/9 and a removable centering plate mounted in the cen- Sl/g tral opening to prevent radial inward movement.

3,683,556 8/1972 Leliaert..............,...................... 2,819,562 H1958 Barnes....................... 2,376,639 5/1945 3/l952 Germany W2 ii CENTRIFUGAL BLASTING WHEEL BACKGROUND OF THE INVENTION The invention relates generally to centrifugal blasting wheels. More specifically, it relates to an improved structure for holding the throwing blades of such wheels.

Centrifugal blasting wheels which are well known in the art are usually constituted by a rotatable wheel formed of a pair of side plates maintained in a spaced apart relationship. A plurality of radially extending blades are mounted between the side plates and receive particulate material from an impeller mounted at the center of the wheel. The blades are subject to wear due to the impact of the blast material on their surfaces and must be replaced periodically. Heretofore, the blades have been designed to be inserted between the side plates from the periphery of the wheel and held inplace by elements such as spring locks, set screws or the like mechanically interengaging each other between the blades and the side plates. Such retaining means have required special removal tools in some cases, extensive time for blade replacement and are themselves subject to wear and therefore require periodic replacement.

It is an object of this invention to provide a novel centrifugal blasting wheel and blades therefor in which the blades, when worn, may be relatively easily removed and replaced.

It is another object of this invention to provide a novel centrifugal blasting wheel and blades therefor in which the blade retaining means is relatively protected from impact by the blast material and therefore itself is capable ofa longer life and consequently need not be replaced periodically.

BRIEF SUMMARY OF THE INVENTION The foregoing and other objects of the invention are achieved in one embodiment by providing a centrifugal blasting wheel in which the throwing blades are dimensioned so as to permit their insertion and removal through the central opening once the impeller and control cage have been removed and are held against outward movement by engagement of surfaces on the back rails of the blades with a spacer having a surface matching those provided on the back rails. Means are provided to prevent radial inward movement of the blades.

BRIEF DESCRIPTION OF THE DRAWING The invention itself is set forth in the claims appended hereto and forming a part of this specification while an understanding of the structure and functioning of an embodiment thereof can be derived from the detailed description taken in conjunction with the figures of the drawing in which:

FIG. I is a side view in section of a centrifugal blasting wheel in accordance with the invention;

FIG. 2 is a view along the lines 2-2 of FIG. 1; and

FIG. 3 is a perspective illustration of a blade constituting an aspect of the invention.

DETAILED DESCRIPTION Referring to FIGS. 1 and 2 of the drawing, there is shown a centrifugal blasting wheel in accordance with the invention. Generally, a complete wheel assembly comprises the wheel itself 2 mounted in the housing 4. A motor 6 rotates the wheel to propel particulate blast material out of an opening 8 in the bottom of the housing. The material itself is supplied through a feed spout 10 to the center of the wheel as will be described.

The wheel 2 comprises a pair of side plates 12 and 14 maintained in a spaced apart relationship by a plurality of circumferentially arranged space means including spacers 16. Each spacer is mounted between the side plates by riveting or swagging its ends 18 in an opening provided for that purpose in the side plates. As may be seen, particularly in FIG. 2, each spacer is formed as cylinders so as to be circular in cross section. A cylindrical sleeve 20 constituting a part of the spacer means encompasses each spacer 16 and is formed from metallic material which is particularly hard so as to resist wear.

In order to mount the wheel 2 in the housing 4 for rotation about its axis, a hub 22 is secured to the side plate 14 by a suitable means such as by bolts (not shown). The hub in turn is pressed onto a bushing 24 which is locked to a motor shaft 26 by a key 27. Thus, upon energization of the motor 6 the wheel will be rotated. The hub 22 is mounted for rotation within a felt seal 28 supported in a circular groove 30 provided in a seal retainer 32 forming a part of the housing 4. While the drive is shown as a direct drive an indirect drive such as one using sheaves and V-belts could be used.

The wheel includes a plurality of circumferentially spaced radially extending blades, each designated generally by reference numeral 34. The blades are equally spacedaround the circumference of the wheel and, as may be seen in this embodiment, number eight. However, the number may be lesser or greater, it being desirable of course that an even number of blades be used to achieve wheel balance. Each blade is provided with a throwing surface 36 and a first or outer end 38 and a second or inner end 40. As may be seen in the illustrated embodiment, the throwing surface 36 adjacent the inner end 40 is curved as shown at 42. In this embodiment, the wheel, as shown in FIG. 2, is intended to be rotated counterclockwise so that the surfaces 42 are curved to the rear of the throwing surface 36 and opposite to the intended direction of rotation. While it is preferred that blades have the curved inner ends shown, this is not necessary as the blades may be provided with straight ends.

As may be best seen in FIG. 3, each blade is provided with side rails 44 which extend slightly forwardly of the throwing surface 36 and rearwardly thereof. Intermediate' the length of each side rail on the rearwardly extending portion thereof are curved shoulders 46 joining the side rail portion 48 starting from the inner end 40 to the portion 50 starting from the outer end 38. As may be seen, strengthening ribs such as shown at 52 may be provided extending transversely of the length of the side rails. When mounted between the wheel, the side rails engage in opposite grooves 53 in the side plates 12 and 14 extending along a radius passing near each spacer sleeve 20. As may be seen, the sleeves overlie the grooves to a slight degree.

The wheel 2 is completed by a hollow vaned impeller 54 mounted at a central opening 56 defined by the inner ends 40 of the blades 34. The impeller is mounted on the shaft 26 by means of a centering plate 58 having a portion 60 extending into one end of the impeller. The centering plate in turn is fastened to the shaft 26 by a cap screw or bolt 61 so that the impeller will be rotated with the wheel when the motor is energized. As may be best seen in FIG. 1, the centering plate 58 is provided with a radially projecting portion or ledge 62 which is in contact with the inner end 40 of each blade 36 adjacent the side plate 14. Surrounding the impeller 54 is an adjustable stationary control cage 64 having a discharge port or slot 66 through which particulate material which has been propelled by the impeller may pass to be engaged by a throwing surface 36 of a blade 34 so as to be propelled thereby out of the opening 8 adjacent a piece part to be cleaned or otherwise treated. One end 68 of control cage 64 engages in an opening in a side wall 70 of the housing 4 and is held there by locking means (not shown) so that it may be adjusted to any desired angular position so as to control the direction of the blast.

Particulate material to be propelled by the blades 34 is supplied to the interior of the hollow impeller by a supply system of which the feed spout is a part. The spout is held in position on the housing 2 by a flange 72 and a retaining clamp 74 movably mounted on the housing by a bolt 76 threaded in boss 78 on the housing wall 70. A threaded clamping stud 80 on the free end of the clamp is screwed down on a boss 82 formed on the feed spout 10 to positively hold the spout in assembled position.

In operation, the wheel is rotated counterclockwise as indicated and at the same time blast material is supplied through the feed spout to the hollow interior of the impeller 54. The vanes of the impeller engaging the material impart a velocity having a radial component thereto so as to propel it through the discharge port 66 of the control cage 64. The material leaving the discharge port contacts the throwing surfaces 36 of the blades 34 as they rotate past that port and are accelerated along those surfaces to be propelled through the opening 8 against the piece part.

As stated, it is periodically necessary to replace the blades as they are worn due to the impact of abrasion of the particulate blast material on their surfaces. In accordance with this invention, this is accomplished as follows: It may be seen from an inspection of the drawing that each blade 34 has a length which is less than the diameter of the central circular opening defined by their inner ends 40. When the blades are mounted in the grooves 53 in the wheel they are held against radial outward movement by the engagement of the curved shoulders 46 of the side rails 44 with the matching surfaces of the sleeves 20. Also, when so mounted a portion of their inner ends 40 engage the ledge 62 of the centering plate 58 so that inward radial movement is prevented, Thus, means are provided to positively hold each blade against inward or outward radial movement.

When it is desired to replace the blades, all that need be done is to loosen the clamp 74 by loosening the bolt 76 and clamping stud 80. The clamp may then be swung out of the way and feed spout l0 removed from the opening in the wall 70 of the housing 4 so as to expose the control cage 64, impeller 54, centering plate 58 and the bolt holding the centering plate on the shaft 26. The bolt may then be unthreaded from the shaft freeing the centering plate and impeller so that they may be removed axially outward of the central opening 56 along with the control cage 64. When this is done, the blades 34 are freed to move radially inward as their inner ends are not longer restrained by the ledge 62 of the centering plate. At this point, or previously if desired, a cover 84 of the housing 4 may be opened and a wear plate 86 removed to expose the outer ends of the blades. This may be necessary for during operation of the wheel particulate material may have entered in whatever space may exist between the blade, side rails 44 and the walls of the grooves 53 in which they are mounted, thus requiring a force to be applied to their outer ends in order to free them for radial inward movement. In any case, the blades are moved radially inward in grooves 53 until they are free of the grooves at which point they may be moved axially out of the central opening through the side wall for, as stated, their length is less than the diameter of the central opening.

Replacement blades may be inserted by passing them into the central opening, engaging the side rails in a pair of opposing grooves and sliding the blade radially outward in the grooves until its movement is stopped by the engagement with a sleeve 20 with the matching curve surfaces 46 on the side rails. As may be seen, the side rail portions 50 are lower than the portions 48 permitting passage of the blades past the spacer sleeves until the surface 46 of the side rails engage the matching surface on the sleeves 20. The control cage, impeller and centering plate may then be reassembled as may the other elements and wheel operation resumed.

Various modifications may be made without departing from the spirit of the invention as set out in the claims. For instance, the side rails need not extend the entire length of the blades but may terminate at orjust after the surfaces 46. Likewise, as indicated, the blade need not be curved. The spacer means constituting the spacer and sleeve may be formed as a unitary element. Other modifications may occur to those skilled in the art and it is intended by the claims to cover all such modifications as come within their scope.

What is claimed as new and desired to be secured by Letters Patent is:

1. In a centrifugal blasting wheel mounted for rotation comprising: a pair of spaced circular side walls; cylindrical spacer means mounted in said side walls and extending therebetween to maintain them in spaced apart relation; a plurality of circumferentially spaced radially extending blades mounted between said side walls; said blades having inner and outer ends and front and rear surfaces, the front surface thereof constituting a throwing surface; said inner ends of said blades defining a central opening; a hollow vaned impeller mounted in said central opening for rotation with the wheel; a stationary control cage encompassing said impeller and having a discharge port; and one of said side walls having an opening therein substantially coextensive with said central opening to provide access to said central opening, said impeller and said control cage; the improvement wherein: each blade being of a length between its inner and outer ends less than the diameter of said central opening and the opening in said one of said side walls; each blade having a side rail extending along its length on either side of said throwing surface and extending away from its rear surface; each side rail having a curved surface matching a surface on said spacer means whereby each said blade may be inserted through said central opening and moved radially outward between said side plates until the matching surfaces on said side rails engage the surface of said spacer means and each said throwing blade will be prevented from further radially outward movement.

2. A centrifugal blasting wheel as defined in claim 1 including a centering plate disposed in said central opening on one side thereof and having a portion engaging the inner ends of said blades.

3. A centrifugal blasting wheel as defined in claim 1 wherein said side plates have a plurality of circumferentially spaced pairs of opposing radially extending grooves formed on the interior thereof and the side rails of each blade engage in a pair of said grooves.

4. A centrifugal blasting wheel as defined in claim 3 wherein each of said pair of grooves extend radially adjacent said spacer means and a portion of said spacer means overlies said grooves.

5. A centrifugal blasting wheel as defined in claim 1 wherein said side rails extend over the entire length of said blades and said side rail surfaces are provided intermediate the length of said side rails and the side rail portion starting from the inner end of a blade extends further away from the surface of the blade than does the side rail portion starting from the outer end of the blade and said surfaces join the two side rail portions.

6. A centrifugal blasting wheel as defined in claim 5 including a centering plate disposed in said central opening on one side thereof and having a portion engaging the inner ends of said blades.

7. A centrifugal blasting wheel as defined in claim 6 wherein said side plates have a plurality of circumferentially spaced pairs of opposing radially extending grooves formed on the interior thereof and the side rails of each blade engage in a pair of said grooves.

8. A blade for use with a centrifugal blasting wheel having a first end and a second end, front and rear surfaces, the front surface thereof constituting a throwing surface extending between said first and second ends, a pair of side rails, one of each pair of side rails extending along the length of the blade on either side of said throwing surface and rearwardly thereof, a first portion of each of said side rails extending further rearwardly of said throwing surface than a second portion thereof.

9. A blade as defined in claim 1 wherein each of said side rails extend the entire length of the blade and said surface of each of said side rails is provided intermediate the length thereof. 

1. In a centrifugal blasting wheel mounted for rotation comprising: a pair of spaced circular side walls; cylindrical spacer means mounted in said side walls and extending therebetween to maintain them in spaced apart relation; a plurality of circumferentially spaced radially extending blades mounted between said side walls; said blades having inner and outer ends and front and rear surfaces, the front surface thereof constituting a throwing surface; said inner ends of said blades defining a central opening; a hollow vaned impeller mounted in said central opening for rotation with the wheel; a stationary control cage encompassing said impeller and having a discharge port; and one of said side walls having an opening therein substantially coextensive with said central opening to provide access to said central opening, said impeller and said control cage; the improvement wherein: each blade being of a length between its inner and outer ends less than the diameter of said central opening and the opening in said one of said side walls; each blade having a side rail extending along its length on either side of said throwing surface and extending away from its rear surface; each side rail having a curved surface matching a surface on said spacer means whereby each said blade may be inserted through said central opening and moved radially outward between said side plates until the matching surfaces on said side rails engage the surface of said spacer means and each said throwing blade will be prevented from further radially outward movement.
 2. A centrifugal blasting wheel as defined in claim 1 including a centering plate disposed in said central opening on one side thereof and having a portion engaging the inner ends of said blades.
 3. A centrifugal blasting wheel as defined in claim 1 wherein said side plates have a plurality of circumferentially spaced pairs of opposing radially extending grooves formed on the interior thereof and the side rails of each blade engage in a pair of said grooves.
 4. A centrifugal blasting wheel as defined in claim 3 wherein each of said pair of grooves extend radially adjacent said spacer means and a portion of said spacer means overlies said grooves.
 5. A centrifugal blasting wheel as defined in claim 1 wherein said side rails extend over the entire length of said blades and said side rail surfaces are provided intermediate the length of said side rails and the side rail portion starting from the inner end of a blade extends further away from the surface of the blade than does the side rail portion starting from the outer end of the blade and said surfaces join the two side rail portions.
 6. A centrifugal blasting wheel as defined in claim 5 including a centering plate disposed in said central opening on one side thereof and having a portion engaging the inner ends of said blades.
 7. A centrifugal blasting wheel as defined in claim 6 wherein said siDe plates have a plurality of circumferentially spaced pairs of opposing radially extending grooves formed on the interior thereof and the side rails of each blade engage in a pair of said grooves.
 8. A blade for use with a centrifugal blasting wheel having a first end and a second end, front and rear surfaces, the front surface thereof constituting a throwing surface extending between said first and second ends, a pair of side rails, one of each pair of side rails extending along the length of the blade on either side of said throwing surface and rearwardly thereof, a first portion of each of said side rails extending further rearwardly of said throwing surface than a second portion thereof.
 9. A blade as defined in claim 1 wherein each of said side rails extend the entire length of the blade and said surface of each of said side rails is provided intermediate the length thereof. 